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journal of orthopaedic & sports physical therapy | volume 44 | number 2 | february 2014 | 59
[ research report ]
Tendinopathy is common in the sporting as well as the general
population,36 with pain and disability often persisting despite
treatment.2 Consequently, premature cessation of work or
an athletic career often occurs, which results in a significant
socioeconomic impact.23
The etiology of tendinopathy is still
unclear; however, histological evidence
consistently demonstrates an absence of
prostaglandin-mediated inflammation.4,11
Consequently, it has been recommended
that the term tendinopathy replace the
traditional term tendinitis for describing
tendon pathology.16 In addition, because
inflammatory infiltrates are absent, it is
recognized that anti-inflammatory strat-
egies are generally ineective for this
condition. This shift in understanding of
pathophysiology has prompted the use
of interventions such as eccentric exer-
cises to be considered as a viable option
for rehabilitation.2 Eccentric exercises
are considered safe,18 and previous work
indicates success with this approach in
the rehabilitation of midportion Achilles
tendinopathies.20,25,27,32
The Alfredson protocol is a program
of eccentric heel-drop exercises for treat-
ing Achilles tendinopathies. It has been
widely adopted in research and clini-
cal practice. The protocol recommends
completion of 180 eccentric repetitions
a day.3 Currently, there is no strong ra-
tionale for this repetition volume.39 The
Alfredson protocol requires patients to
continue with the exercise even if pain
STUDY DESIGN: Randomized clinical trial.
OBJECTIVES: To compare the eectiveness of
the Alfredson eccentric heel-drop protocol with a
“do-as-tolerated” protocol for nonathletic individu-
als with midportion Achilles tendinopathy.
BACKGROUND: The Alfredson protocol recom-
mends the completion of 180 eccentric heel drops
a day. However, completing this large number of
repetitions is time consuming and potentially un-
comfortable. There is a need to investigate varying
exercise dosages that minimize the discomfort yet
retain the clinical benefits.
METHODS: Twenty-eight individuals from
outpatient physiotherapy departments were ran-
domized to either the standard (n = 15) or the do-
as-tolerated (n = 13) 6-week intervention protocol.
Apart from repetition volume, all other aspects of
management were standardized between groups.
Tendinopathy clinical severity was assessed
with the Victorian Institute of Sport Assessment-
Achilles (VISA-A) questionnaire. Pain intensity was
assessed using a visual analog scale (VAS). Both
were assessed at baseline, 3 weeks, and 6 weeks.
Treatment satisfaction was assessed at week 6.
Adverse eects were also monitored.
RESULTS: There was a statistically significant
within-group improvement in VISA-A score for both
groups (standard, P = .03; do as tolerated, P<.001)
and VAS pain for the do-as-tolerated group (P =
.001) at week 6, based on the intention-to-treat
analysis. There was a statistically significant
between-group dierence in VISA-A scores at week
3, based on both the intention-to-treat (P = .004)
and per-protocol analyses (P = .007), partly due to
a within-group deterioration at week 3 in the stan-
dard group. There were no statistically significant
between-group dierences for VISA-A and VAS pain
scores at week 6, the completion of the interven-
tion. There was no significant association between
satisfaction and treatment groups at week 6. No
adverse eects were reported.
CONCLUSION: Performing a 6-week do-as-
tolerated program of eccentric heel-drop exercises,
compared to the recommended 180 repetitions
per day, did not lead to lesser improvement for
individuals with midportion Achilles tendinopathy,
based on VISA-A and VAS scores.
LEVEL OF EVIDENCE: Therapy, level 2b. J
Orthop Sports Phys Ther 2014;44(2):59-67. Epub
21 November 2013. doi:10.2519/jospt.2014.4720
KEY WORDS: eccentric exercise, pain,
repetition volume, treatment satisfaction, VISA-A
1Physical Therapy Department, Stirling Community Hospital, NHS Forth Valley, Stirling, UK. 2Physiotherapy, School of Health Sciences, Queen Margaret University, Edinburgh,
UK. This study was approved by the Research Ethics Committees of East of Scotland Research Ethics Service and Queen Margaret University. The authors certify that they
have no aliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article. Address
correspondence to Dr Chee-Wee Tan, Queen Margaret University, Musselburgh EH21 6UU, United Kingdom. E-mail: ctan@qmu.ac.uk Copyright ©2014 Journal of Orthopaedic
& Sports Physical Therapy®
MARC STEVENS, PT, MSc1 • CHEE-WEE TAN, PT, PhD2
Eectiveness of the Alfredson
Protocol Compared With a Lower
Repetition-Volume Protocol for
Midportion Achilles Tendinopathy:
A Randomized Controlled Trial
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is experienced; however, the patient is
advised to stop if the pain becomes dis-
abling. This raises significant practical
issues related to exercise adherence and
treatment satisfaction, which may impact
the overall treatment ecacy of the pro-
tocol. In addition, most of the previous
research showing success with this ap-
proach has been conducted on athletic
(or at least physically active) individu-
als.31,35 In studies that have investigated
the eectiveness of the eccentric exercises
on a nonathletic population, the results
have been less striking.25,28 Therefore, the
objective of this study was to compare the
eectiveness of the Alfredson eccentric-
exercise protocol with that of a modi-
fied protocol that allows participants to
perform the exercises within their toler-
ance in both active and more sedentary
individuals with midportion Achilles
tendinopathy.
METHODS
Study Design
The present study was a prospec-
tive, outcomes assessor–blinded
and statistician-blinded, random-
ized clinical trial evaluating participants
over a period of 6 weeks. Participants
were randomly allocated to 2 groups,
both of which were taught the Alfredson
eccentric-exercise protocol.3 Those in the
standard group were asked to perform
180 repetitions of the exercises per day,
whereas those in the “do-as-tolerated”
group were asked to perform the rep-
etition amount they could reasonably
achieve.
Participants and Recruitment
The protocol for this study was approved
by the Research Ethics Committees of the
United Kingdom National Health Ser-
vice and of Queen Margaret University.
Potential participants were identified on
clinic waiting lists and were sent letters of
invitation with details of the study. Poten-
tial participants were informed that they
could withdraw from the study at any
point and their care would not be aect-
ed by this decision. Participants provided
informed consent and were examined as
per normal assessment procedures. Safe-
ty and adverse eects were constantly
monitored throughout the duration of
the study by the treating clinicians.
Inclusion and Exclusion Criteria
The inclusion criteria were that the par-
ticipants had to (1) be at least 18 years
of age, (2) have symptoms lasting more
than 3 months, and (3) have midportion
Achilles tenderness (2-7 cm proximal to
insertion) on palpation during or after
activity. The exclusion criteria were (1)
tendon insertion pain; (2) fracture of
the aected lower limb within the last 12
months; (3) presence of bursitis, rheuma-
toid arthritis, diabetes, or other systemic
disorders; (4) previous surgical interven-
tion (within the last 12 months) or ste-
roid injection (in the last month) near the
Achilles tendon; (5) previous experience
with eccentric-loading exercises; (6) sud-
den onset of symptoms suggesting partial
rupture; and (7) any congenital deformity
aecting the lower limb.
Procedures
Eight senior musculoskeletal physiother-
apists collected data for this study. All
data collectors and treating clinicians re-
ceived standardized training concerning
the study protocol, obtaining informed
consent, assessment/diagnostic criteria,
data recording, eccentric-exercise train-
ing protocol, and training progression.
One of the authors (M.S.) provided all
training. To minimize bias, the authors
and the treating clinicians were not in-
volved in data collection.
Eight clinical sites (2 district hospi-
tals and 6 general practitioner practices)
were utilized. Once the participant joined
the study, baseline data using standard-
ized protocols were obtained by the data
collectors. Each participant was seen by
the same treating clinician throughout
the duration of the study. The treating
clinician taught the participant the ex-
ercise technique and provided written
instructions and a training diary for the
participant to record the volume of ex-
ercise completed each day. At this stage,
the treating clinician obtained the par-
ticipant’s group assignment by contacting
the department secretary, who randomly
selected a sealed, opaque envelope de-
tailing the number of repetitions to be
completed per day (standard versus do as
tolerated). Participants were encouraged
not to discuss their group assignment
with anyone throughout the duration
of their involvement in the trial, to en-
sure that the data collectors and authors
were blinded to group allocation. Out-
comes were re-evaluated 3 and 6 weeks
later, at the participants’ follow-up ap-
pointments. At week 3, correct exercise
technique was ensured by the treating
clinicians. At week 6, data on treatment
satisfaction were also obtained.
Eccentric Exercise/Interventions
Both groups performed eccentric heel-
drop exercises as described by Alfredson
et al.3 The standard group performed 180
repetitions a day, by completing 3 sets
of 15 repetitions in 2 training positions
(knee fully extended and knee slightly
flexed) twice a day. The do-as-tolerated
group also completed the eccentric heel-
drop exercises in both training positions
twice a day, with the recommendation
that they achieve a repetition volume
similar to that of the standard group, but
they were also told that they could choose
to complete a repetition volume that was
tolerable. No further instructions were
provided on the minimum or maximum
repetition volume. Both groups were ad-
vised to exercise to discomfort but not
excessive pain.3 Participants were en-
couraged to progress training by wear-
ing weighted backpacks if the exercise
became less painful. They were also ad-
vised to avoid high-impact or sporting
activities to allow relative rest until the
pain subsided.
Outcome Measures
The Victorian Institute of Sport Assess-
ment-Achilles The Victorian Institute of
Sport Assessment-Achilles (VISA-A) was
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journal of orthopaedic & sports physical therapy | volume 44 | number 2 | february 2014 | 61
chosen as the primary outcome measure
for this study. This questionnaire consists
of 8 questions assessing pain, function,
and ability to participate in activity, with
a score ranging from 0 to 100, higher
scores indicating lower clinical severity of
the condition. The VISA-A is deemed val-
id and reliable in individuals with Achil-
les tendinopathy24 and is recommended
for the assessment of Achilles tendinopa-
thy.7,14,33 For this study, a minimum clini-
cally important dierence (MCID) of 15
points was considered clinically signifi-
cant, which is larger than that reported
by Silbernagel et al.30
Visual Analog Scale for Pain A visual
analog scale (VAS), on which 0 indicated
no pain and 100 the worst pain imagin-
able, was used as a secondary measure of
perceived pain intensity. The VAS is con-
sidered to be valid, reliable, and sensitive
to change,38 and has been used to evalu-
ate tendinopathy-related pain.2 For this
study, an MCID of 15 points was consid-
ered clinically significant.34
Treatment Satisfaction Treatment sat-
isfaction was also included as a second-
ary outcome measure. Participants were
asked to rate their satisfaction with
treatment as poor, moderate, good, or
excellent.9
Sample-Size Determination
The VISA-A was the primary outcome
measure for this study. A total of 30
participants were required to detect a
clinically significant between-group dif-
ference of 15 points, assuming an esti-
mated standard deviation of 14 points.
Power and alpha level were set a priori
at 80% and 5%, respectively. A VISA-
A change score of 15 points was chosen
based on clinical judgment, which is
wider than the clinically significant dif-
ference of 10 points used in the study by
Silbernagel et al.30
Statistical Analysis
Statistical analysis was conducted in a
blinded manner, using an intention-to-
treat (ITT) approach. A multiple-im-
putation approach, using SPSS Version
17 (SPSS Inc, Chicago, IL), was used to
handle missing data. Data were missing
in 21.4% of the participants, accounting
for 6.7% of the total data. Little’s test19
showed that the data were missing com-
pletely at random (χ216 = 12.45, P = .071).
A per-protocol (PP) analysis was also
performed and compared to the results
of the ITT analysis to judge the extent to
which the missing data might have influ-
enced the results.
VISA-A and VAS pain data were ana-
lyzed separately using 2-by-3, 2-way,
mixed-design analyses of variance. The
between-subject factor was the repeti-
tion volume performed (standard versus
do as tolerated), and the within-subject
factor was the assessment time (baseline,
week 3, and week 6). The chi-square test
with the Yates correction test was used to
analyze the association between partici-
pants’ treatment satisfaction and their al-
located treatment groups. The dierences
in mean number of exercise repetitions
per day performed by the groups were
analyzed using the Mann-Whitney test.
Appropriate post hoc analysis was used
to analyze dierences.
Correlational analysis was performed
to determine the relationships between
(a) the activity levels of participants (ac-
tive or sedentary) and mean exercise rep-
etition volume performed per day, and (b)
the participants’ treatment satisfaction
ratings with changes in VISA-A and VAS
pain scores.
RESULTS
Participants
Seventy-two individuals were
identified, of whom 28 (11 men, 17
women) were recruited and ran-
domly allocated to the treatment groups.
Trial recruitment and retention data are
provided in FIGURE 1. Forty-four poten-
tial participants were not included in
the study for the following reasons: de-
clined participation in the study (n = 9),
diagnosis of insertional tendinopathies
(n = 19), inability to perform or previous
experience with eccentric exercises for
Assessed for eligibility, n = 72
Excluded, n = 44
• Not meeting inclusion criteria,
n = 35
• Refused to participate, n = 9
Randomized, n = 28
Enrollment
Allocated to standard Alfredson
protocol, n = 15
• Received allocated intervention,
n = 15
Allocated to “do-as-tolerated”
protocol, n = 13
• Received allocated intervention,
n = 13
AllocationFollow-upAnalysis
Lost to follow-up, n = 4
• Week 3, n = 1
• Week 6, n = 3
Lost to follow-up, n = 2
• Week 3, n = 1
• Week 6, n = 1
Per-protocol analysis, n = 11
Intention-to-treat analysis, n = 15
Per-protocol analysis, n = 11
Intention-to-treat analysis, n = 13
FIGURE 1. CONSORT flow algorithm outlining the participant enrollment, allocation, follow-up, and attrition
numbers for this study.
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Achilles tendinopathies (n = 7), equivo-
cal diagnoses (n = 2), complete tendon
rupture (n = 1), suspected rheumatoid
arthritis (n = 3), and ankle fracture with-
in the last 12 months (n = 3). Twenty-six
(93%) participants provided data at week
3, and 22 participants (79%) at week 6.
Therefore, 6 (21%) participants were lost
to follow-up. TABLE 1 provides the partici-
pants’ characteristics for the 2 treatment
groups.
Repetition Volume
The mean numbers of repetitions com-
pleted per day by the participants were
112 (95% confidence interval [CI]: 85,
139) and 166 (95% CI: 150, 182) for the
do-as-tolerated and standard groups,
respectively. There was a significant dif-
ference between the volumes of eccentric
exercise completed for each group (U =
31.0, P = .001). The level of association
between the exercise repetition volume
and the activity level of participants (ac-
tive or sedentary) was not significant (rpb
= 0.21, P = .37).
VISA-A Scores
Both groups improved in perceived clini-
cal severity over the 6-week intervention
program (TABLES 2 and 3). The do-as-
tolerated group, using the ITT analysis,
demonstrated a nearly linear improve-
ment over time, with a mean VISA-A
score of 47.1 at baseline improving to
62.5 at week 6, which resulted in a sta-
tistically significant mean dierence of
15.4 points (95% CI: 9.8, 21.1). Data for
the PP analysis were similar, with 49.9 at
baseline, 63.2 at 6 weeks, and a change
of 13.3 points (95% CI: 7.7, 18.8). For the
standard-protocol group, perceived clini-
cal severity initially deteriorated, then,
by week 6, improved above its baseline
value. In this group, using the ITT analy-
sis data, the baseline VISA-A score was
49.6 (49.2 for PP analysis) and eventu-
ally improved to 58.7 (57.4 for PP analy-
sis), resulting in a statistically significant
mean dierence of 9.1 points (95% CI:
0.9, 17.4; P = .03) with the ITT analysis
and 8.2 points (95% CI: –1.4, 17.8; P =
.09) with the PP analysis.
The between-group dierence in VI-
SA-A change scores was not statistically
significant at week 6 (ITT, P = .20; PP,
P = .32) (TABLES 2 and 3). But there was
a statistically significant dierence in
VISA-A change scores between groups
at week 3 (ITT, P = .004; PP, P = .007),
which may be partially attributed to the
worsening in VISA-A score for the stan-
dard group at that time.
The results of the ITT (TABLE 2) and PP
(TABLE 3) analyses for VISA-A data were
compared to examine the influence of
missing data on the results. For the stan-
dard-protocol group, the 95% CI for the
within-group change scores from base-
line to 6 weeks was slightly narrower with
the ITT analysis (0.9, 17.4) compared to
the PP analysis (–1.4, 17.8). Likewise,
the 95% CI for the within-group change
score at week 3 for the do-as-tolerated
group was slightly narrower with the ITT
analysis (0.1, 18.2) compared to the PP
analysis (–1.8, 20.2).
This resulted in the within-group
change score at week 6 for the standard-
protocol group being statistically signifi-
cant with the ITT analysis but not with the
PP analysis. The results for the between-
group comparisons were similar when
using either the ITT or PP analysis, with
a significant dierence between groups
present at week 3 but not at week 6.
VAS Pain Scores
For the standard-protocol group, based
on the ITT analysis, the mean VAS pain
score improved from a baseline of 52.2
mm to 40.4 mm (from 58.2 mm to 42.1
mm with the PP analysis). For the same
time period, the do-as-tolerated group
improved from 55.4 mm to 31.5 mm
(from 53.6 mm to 34.7 mm with the PP
analysis). The between-group dierence
for VAS pain change score from baseline
was not statistically significant at week 3
(ITT, P = .23; PP, P = .61) and at week 6
(ITT, P = .14; PP, P = .73) (TABLES 2 and 3).
The overall results with the ITT (TABLE
2) and PP (TABLE 3) analyses for VAS pain
were similar to the results for the VISA-
A scores. The within-group VAS pain
change score for the standard group at
week 6 had a slightly narrower 95% CI
with the ITT analysis (–24.0, 0.2) com-
pared to the PP analysis (–30.2, –2.0).
This did not have an impact on the re-
sults. The standard-group VAS pain
within-group change score at week 6
with the PP analysis returned a statisti-
cally significant result compared to that
of the ITT analysis.
Treatment Satisfaction
FIGURE 2 shows the satisfaction rating of
participants at week 6. Five participants
(38.4%) in the do-as-tolerated group
and 4 participants (26.7%) in the stan-
dard group reported their satisfaction
as excellent. No participants in either
group reported poor satisfaction with
TABLE 1 Baseline Demographics and Clinical
Characteristics of Participants (n = 28)*
*Values are mean SD except for gender and activity level.
†Defined as participating in recreational or competitive activities that loaded the lower limb more
than 4 times a week for more than 30 minutes at a time.
Standard Volume (n = 15) Do as Tolerated (n = 13)
Age, y 48.2 10.8 49.2 11.3
Body weight, kg 88.3 14.0 84.5 14.6
Height, m 1.68 0.13 1.75 0.10
Body mass index, kg/m231.6 6.1 29.5 5.3
Duration of symptoms, mo 6.2 2.1 8.9 5.1
Men/women, n 6/9 5/8
Active†/sedentary, n 6/9 7/6
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the treatment received. Treatment sat-
isfaction was not associated with type of
treatment received at week 6 (χ2 = 0.50, P
= .92). There was no significant correla-
tion between the participants’ treatment
satisfaction ratings and the changes in
VISA-A and VAS pain scores (τ = 0.28, P
= .09 and τ = –0.27, P = .10, respectively).
DISCUSSION
There was no statistically sig-
nificant dierence in change scores
between the standard group and the
do-as-tolerated group for VISA-A and
VAS pain scores at the conclusion of the
6-week intervention, based on both the
ITT and PP analyses. However, there was
a statistically significant between-group
dierence in VISA-A scores at week 3
with both the ITT and PP analyses. This
was partially attributed to the worsening
VISA-A scores at week 3 for the group
training using the standard protocol. For
both groups, the ITT analysis indicated
a statistically significant within-group
improvement in VISA-A and VAS pain
scores after the 6-week intervention.
Similar results were found with the PP
analysis, with the exception that the with-
in-group improvement in VISA-A score
for the standard training protocol group
was no longer significant.
VISA-A and Pain Scores
Within-Group Results Both groups in
our study had within-group VISA-A and
VAS pain change scores at week 6 that
were similar to those previously reported
in the literature on the Alfredson proto-
col.12,20,25,28,31 Most similar to the results
of our study was the 11.5-point VISA-A
improvement after a 12-week eccentric-
exercise program, previously reported
by Sayana and Maulli.28 Rompe et
al25 reported a slightly larger change in
VISA-A (25.0 points) after a 16-week
program, whereas Herrington and Mc-
Culloch12 found VISA-A improvements
of approximately 19.0, 31.0, and 36.0
points from baseline at weeks 4, 8, and
12, respectively.
Similar improvements in pain inten-
sity over time were also reported by previ-
ous authors. Silbernagel et al31 reported
a median improvement from baseline
on the VAS of 9, 14, and 28 mm at 6, 9,
and 12 weeks, respectively. Mafi et al20
found a VAS pain score improvement of
57 mm after a 12-week program, but only
in participants who were satisfied with
treatment.
It is important to note that our study
did not follow the participants after the
6-week program. The total exercise vol-
ume would be much higher over a longer
period (eg, 1-5 years) and may be asso-
ciated with clinical improvements.29,35 It
would be of interest for future research
to investigate the long-term influence of
repetition volume on clinical progress.
Between-Group Results In the pres-
ent study, with both ITT and PP analy-
ses there was a statistically significant
between-group dierence in VISA-A
TABLE 2
Outcome Measures at Baseline, Week 3, and Week 6
for Participants in the Standard (n = 15) and
Do-as-Tolerated (n = 13) Groups (Intention-to-Treat Analysis)
Baseline Week 3 P Value (Eect Size) Week 6 P Value (Eect Size)
Outcome measures*
VISA-A
Standard 49.6 10.2 41.0 13.0 58.7 13.0
Do as tolerated 47.1 15.6 56.2 19.7 62.5 12.8
Pain VAS, mm
Standard 52.2 15.0 51.3 18.4 40.4 17.9
Do as tolerated 55.4 18.4 46.6 23.6 31.5 18.7
Within-group change score from baseline†
VISA-A
Standard –8.6 14.4 (–16.6, –0.6) P = .04 9.1 14.9 (0.9, 17.4) P = .03
Do as tolerated 9.1 14.9 (0.1, 18.2) P = .05 15.4 9.3 (9.8, 21.1) P<.001
Pain VAS, mm
Standard –0.9 17.4 (–10.6, 8.7) P = .83 –11.9 21.9 (–24.0, 0.2) P = .05
Do as tolerated –8.7 15.4 (–18.1, 0.6) P = .06 –23.9 19.2 (–35.5, –12.3) P = .001
Between-group dierence in change score‡
VISA-A 17.7 (6.2, 29.1) P = .004 (1.23) 6.3 (–3.6, 16.1) P = .20 (0.42)
Pain VAS, mm –7.8 (–20.7, 5.1) P = .23 (0.45) –12.0 (–28.1, 4.1) P = .14 (0.55)
Abbreviations: VAS, visual analog scale; VISA-A, Victorian Institute of Sport Assessment-Achilles.
*Values are mean SD.
†Values are mean SD (95% confidence interval), except where indicated otherwise.
‡Values are mean (95% confidence interval), except where indicated otherwise.
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scores at week 3. This dierence was also
clinically significant, based on an MCID
of 15 points for the VISA-A. This dif-
ference was attributed to a statistically
significant worsening of VISA-A score
in the standard group, combined with
a moderate but non–statistically signifi-
cant improvement in VISA-A score in the
do-as-tolerated group. This finding may
have implications for eccentric-exercise
prescription dosage, suggesting that the
do-as-tolerated approach may prevent
this initial worsening of the condition.
In contrast, similar studies with fol-
low-up periods of 2 to 4 weeks have ob-
served a general improvement in VISA-A
and Knee injury and Osteoarthritis Out-
come Score for patients undergoing ec-
centric-loading exercises.12,22 In another
study, there was only a slight, non–statis-
tically significant worsening in functional
index of the leg and lower limb scores.8
Therefore, further investigation of the
short-term impact of adhering to a pro-
tocol of 180 repetitions a day may be war-
ranted to verify our findings. This is also
important for clinicians looking for a less
demanding but equally eective alterna-
tive protocol to the 180-repetitions-per-
day protocol.
TABLE 3 Outcome Measures at Baseline, Week 3, and Week 6 for Participants in the
Standard (n = 11) and Do-as-Tolerated (n = 11) Groups (Per-Protocol Analysis)
Abbreviations: VAS, visual analog scale; VISA-A, Victorian Institute of Sport Assessment-Achilles.
*Values are mean SD.
†Values are mean SD (95% confidence interval), except where indicated otherwise.
‡Values are mean (95% confidence interval), except where indicated otherwise.
Baseline Week 3 P Value (Eect Size) Week 6 P Value (Eect Size)
Outcome measures*
VISA-A
Standard 49.2 10.4 39.2 11.0 57.4 12.4
Do as tolerated 49.9 14.2 59.1 18.9 63.2 11.8
Pain VAS, mm
Standard 58.2 12.0 53.8 20.4 42.1 17.9
Do as tolerated 53.6 16.8 45.6 22.8 34.7 16.5
Within-group change score from baseline†
VISA-A
Standard –10.0 13.5 (–19.1, –0.9) P = .03 8.2 14.3 (–1.4, 17.8) P = .09
Do as tolerated 9.2 16.3 (–1.8, 20.2) P = .09 13.3 8.3 (7.7, 18.8) P<.001
Pain VAS, mm
Standard –4.4 16.4 (–15.4, 6.6) P = .40 –16.1 21.0 (–30.2, –2.0) P = .03
Do as tolerated –8.0 16.8 (–19.3, 3.3) P = .14 –18.9 16.1 (–29.8, –8.1) P = .003
Between-group dierence in change score‡
VISA-A 19.2 (5.8, 32.5) P = .007 (1.42) 5.1 (–5.3, 15.5) P = .32 (0.36)
Pain VAS, mm –3.6 (–18.4, 11.1) P = .61 (0.21) –2.8 (–19.5, 13.9) P = .73 (0.13)
0
Moderate
Poor Good Excellent
10
20
30
40
50
60
Percentage
Standard Do as tolerated
Treatment Satisfaction
FIGURE 2. Treatment satisfaction for the eccentric-exercise program at week 6 for the Alfredson protocol (standard
group) and the “do-as-tolerated” group. There was no significant association between reported treatment
satisfaction and allocated treatment group.
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journal of orthopaedic & sports physical therapy | volume 44 | number 2 | february 2014 | 65
Furthermore, looking at the 95% CIs
for the VISA-A between-group change
scores at 6 weeks, the lower limits are
–3.6 points (ITT analysis) and –5.3
points (PP analysis). As these values are
much smaller than the 15-point MCID
for the VISA-A, the do-as-tolerated regi-
men may not be inferior to the standard
protocol. In contrast, the 95% CI upper
limits for the between-group VISA-A
change scores are 16.1 points with the
ITT analysis and 15.5 points with the PP
analysis, leaving open the possibility of a
clinically meaningful benefit of the do-
as-tolerated regimen over the standard
regimen (ie, an MCID for the VISA-A of
greater than 15 points may be present).
For the pain VAS scores, there were
no statistically or clinically significant
between-group dierences at either week
3 or week 6. A close look at the 95% CIs
of these dierences reveals that the upper
limits, indicating less pain reduction for
the do-as-tolerated regimen compared
to the standard regimen, have an MCID
of less than 15 mm, providing confidence
that the do-as-tolerated regimen is not
less eective than the standard regimen.
In contrast, the lower limits of the 95%
CIs, which are greater than the 15-mm
MCID for pain, leave open the possibility
of a clinically significant greater benefit
of the do-as-tolerated regimen.
Eccentric-Exercise Load
Based on our results, defining the opti-
mal dosage (duration, frequency, and in-
tensity) of eccentric exercises is necessary
to rehabilitation for tendinopathy. From
the perspective of individualized rehabili-
tation, an appropriate clinical predictor
for guiding exercise dosage may be help-
ful. This potential clinical predictor could
simply be based on the aggravation of
symptoms or a heuristic process used by
patients who have shown optimal clinical
improvements. For example, Silbernagel
et al29 used a pain-monitoring model to
help with exercise adherence and to pre-
vent overloading and underloading of the
tissue. Such a strategy may allow patients
to take a more active role in the manage-
ment of their condition. One potential
benefit of active patient management is
improved self-ecacy, which has been
linked to positive outcomes for treatment
of musculoskeletal conditions.21
An often-mentioned threshold for
good adherence to an eccentric-exercise
regimen is above 75% of the total desired
exercise volume (eg, 135 of 180 repeti-
tions).10,26,28 In our study, the standard-
regimen group achieved a mean exercise
volume that was above this threshold.
In contrast, the exercise volumes for
the do-as-tolerated group fell below this
threshold. If the do-as-tolerated group is
generalizable to patients displaying mod-
erate adherence to exercise programs,
this implies that these patients could
potentially still benefit from a modified
Alfredson protocol.
Limitations
Though the clinical diagnosis of midpor-
tion Achilles tendinopathy in this study
was made by experienced clinicians, it
can be argued that diagnostic imaging,
ultrasound, or magnetic resonance im-
aging15 should have been considered to
confirm the diagnosis. Although both im-
aging techniques can locate lesions, they
cannot dierentiate between tendinosis
and partial rupture.5 Also, pathological
findings correlate poorly with patient
symptoms.23 Khan et al17 suggested that
imaging may oer little additional infor-
mation to experienced clinicians.
Previous studies have included perfor-
mance-related outcome measures such as
the countermovement jump, drop coun-
termovement jump, hopping, eccentric/
concentric toe raise, and standing toe
raise test.30 The rationale for these per-
formance-related outcomes is the assess-
ment of the tissue-remodeling aspect of
eccentric exercises through mechanically
loading the musculotendinous struc-
ture.30 Future studies should consider
adding these types of outcome measures.
While the VISA-A may be considered
a condition-specific measure, it might
have been beneficial to include a more
generic outcome measure to capture
more functional aspects of outcomes.
One potential valid, reliable, and respon-
sive generic questionnaire for lower-limb
conditions is the Lower Extremity Func-
tional Scale,6 which has shown good psy-
chometric properties in single-condition
studies.1,13,37 However, there are currently
no studies examining the psychometric
properties of the Lower Extremity Func-
tional Scale for Achilles tendinopathy.
While all data collectors received stan-
dardized training on the study protocol,
the interrater and intrarater reliability of
the data collectors was not determined.
A future refinement of this study would
either introduce reliability testing or re-
duce the number of data collectors. The
numerous data collectors in the present
study were the result of a pragmatic deci-
sion to use 1 data collector at each of the
clinical sites.
CONCLUSION
At the completion of a 6-week
heel-drop eccentric-exercise pro-
gram, there were no statistically
significant dierences in VISA-A and
pain VAS change scores between a group
of patients with midportion Achilles ten-
dinopathy who performed 180 repeti-
tions of the exercise per day and a group
that was instructed to do the number of
repetitions based on tolerability. Both
groups showed statistically and clinically
significant improvement in pain and
VISA-A scores after 6 weeks. However,
there was a statistically significant dete-
rioration of VISA-A scores observed for
those performing 180 repetitions daily
at week 3. Further research is required
to determine the optimal parameters of
eccentric exercise in the management of
midportion Achilles tendinopathy. t
KEY POINTS
FINDINGS: There was no difference in
VISA-A and pain change scores between
2 groups of patients with midportion
Achilles tendinopathy who performed
heel-drop eccentric exercises (180 rep-
etitions daily compared to do as toler-
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66 | february 2014 | volume 44 | number 2 | journal of orthopaedic & sports physical therapy
[
research report
]
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the end of the 6-week intervention.
IMPLICATIONS: As opposed to using a fixed
number of repetitions, patient tolerance
of the exercise may need to be consid-
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for a program of eccentric heel-drop
exercises to address midportion Achilles
tendinopathy.
CAUTION: The study included a limited
number of participants, and there was
no follow-up beyond the 6 weeks of the
study. Future research needs to system-
atically investigate what the proper dos-
age of exercise is for this condition.
ACKNOWLEDGEMENTS: The authors would like
to thank the patients and staff at NHS Forth
Valley who kindly contributed to this study.
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journal of orthopaedic & sports physical therapy | volume 44 | number 2 | february 2014 | 67
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